1. field of the Invention
This invention relates to ankle prosthesis.
2. Description of the Prior Art
The ankle joint is a frequent source of disability in patients with rheumatoid arthritis, post-traumatic degenerative arthritis and, occasionally, avascular necrosis of the talus. Adequate malleoli and ligamentous stability are mandatory for proper functioning of an ankle prosthesis.
Fusion has been the common treatment for the severely painful arthritic ankle joint, sacrificing motion in order to gain pain relief. In addition, literature reveals that ankle fusion has additional problems of non-union, infection, loss of position and need for repeat surgery. A solid ankle fusion places an additional strain on the knee and tarsal joints on that same side. If problems exist in these joints, as in rheumatoid arthritis, this added strain can cause their symptoms to become steadily worse. If no problems exist, painful degenerative changes frequently occur in the talonavicular joint.